1. Field of the Invention
The present invention relates to: a thin film suitable for use as an electronic part; a method and an apparatus for forming the thin film; and an electronic component incorporating the thin film.
2. Description of the Related Art
Thin films have a very wide role in today's society and are applied to various kinds of daily products such as wrapping paper, magnetic tape, capacitors or semiconductors. Without these thin films, current high performance or size reducing technology could not be achieved.
Methods for producing thin films that satisfy industrial demands have been undergoing various developments, for example, thin films earmarked for wrapping paper, magnetic tape, capacitors, etc., are produced by combining a vacuum vapor deposition process with a sequential rolling process which is considered to have an advantage in high-speed mass production. In such a method, a material to be deposited (hereinafter, simply referred to as a "deposition material") and a material as a base substrate where the deposition material is deposited are selected depending on the use of the thin film. When necessary, reaction gas may be introduced into a vacuum chamber or the base substrate may be provided with an electric potential in order to form a thin film with the desired characteristics.
A magnetic recording medium with long length can be obtained by using a deposition material containing magnetic elements (e.g., Co, Ni or Fe) and performing reaction deposition while introducing an oxygen gas into the vacuum chamber. In the case of a semiconductor, a sputtering method is generally used.
A thin film made of resin is formed by a coating method. Reverse coating or die coating is industrially employed as a method for providing a coating of resin on the base substrate. Generally, a material is diluted with a solvent before being coated, dried and cured on the base substrate. By a usual coating method, the thickness of the coating material deposited is generally several microns or more. Therefore, in order to form an extremely sheer resin thin film (herein, a "sheer" resin thin film refers to a "thin" resin thin film), the coating material needs to be diluted with a solvent. The lowest limit of the thickness of the resin thin films formed by the above-described methods is, in most of the cases, around 1 .mu.m. Even when the coating material is diluted with the solvent, a resin thin film with a thickness of 1 .mu.m or less is hard to obtain. Additionally, dilution with a solvent tends to cause defects in the dried coating film and is associated with other problems including environmental problems.
Recently, various composite thin films made from laminated thin films of different kinds have become available and have been used in various industrial fields. An application of composite thin films as chip-shaped electronic components has been receiving much attention. The composite thin films allow for the size reduction of, while still maintaining a high performance, for example, capacitors, coils, resistors or combined components thereof and have already been produced and the market for such products is expanding.
As described above, various methods are available for forming resin thin films. However, by the general coating method, the thickness of the coating material would be several microns or more at the thinnest. Therefore, in order to form an extremely sheer resin thin film, the coating material needs to be diluted with a solvent. Even when the coating material is diluted with a solvent, a resin thin film with a thickness of 1 .mu.m or less is hard to obtain. Additionally, dilution with a solvent tends to cause defects in the dried coating film and is associated with other problems including environmental problems.
In the case of a laminate film, adhesion between the film layers is important as well as the performance of each film layer. Insufficient adhesion between the film layers will cause a minor separation between the film layers during subsequent production steps or during actual usage. Such a minor separation often results in separation of the entire adhesion area between the film layers. Therefore, from a practical standpoint, such a problem needs to be solved.